Recently, organic light-emitting diodes have had many advantages, such as being self-luminous, having a wide view angle, fast response, high contrast, low energy consumption, being green, having a long life, being ultra-thin, and having a flexible display, which could be focused on next-generation display technology.
Refer to FIG. 1, a typical OLED light emitting device comprises a glass substrate 10, an indium tin oxide (ITO) anode 20, an organic light-emitting layer 30, and a cathode 40; the organic light-emitting layer 30 is sandwiched between the ITO anode 20 and the metal cathode 40. The holes of the anode 20 and the electrons of the cathode 40 are combined in the organic light-emitting layer 30 by at applying a voltage, a light A1 could be generated by stimulating the organic material.
However, most of the light A1 cannot output an emitting surface of the OLED light emitting device and emit to a side of the emitting surface due to the influence of the reflection and the refraction between the glass substrate 10 and the surface layer of the air area, so that a ratio of the light outputted from the emitting surface and all of the light A1 emitted from the light-emitting layer 30 (light-emitting efficiency of the OLED light emitting device) is lower, and the development of the OLED light emitting device could be limited. Therefore, improving the light-emitting efficiency of the OLED light emitting device is an urgent problem.